A parliamentary secretary is a member of a Parliament in the Westminster system who assists a more senior minister with his or her duties. In several countries the position has been re-designated as assistant minister.

A Parliamentary Private Secretary (PPS), on the other hand, is a Member of Parliament who acts as an unpaid assistant to an individual minister, but has no ministerial role, although is expected to support the government at all times.

During Jean Chrétien's term as Prime Minister of Canada, parliamentary secretaries were set to two-year terms and the post was used as a reward for weary backbenchers. Their duty was to answer questions and table reports on behalf of ministers when they were unable to be present in the house.

Chrétien's successor as Canadian Prime Minister, Paul Martin, when sworn-in in 2003, promised a new role for parliamentary secretaries. They would now be sworn into the privy council, giving them access to some secret documents, and allowing them to attend Canadian Cabinet meetings and be assigned specific files by ministers. This replaced the positions of Secretaries of State which had been employed under Chrétien.

In Australia, parliamentary secretaries are appointed in the federal government and most state governments. At the federal level, the Ministers of State Act 1952 provides for the Prime Minister to appoint a member from either house of Parliament to be a parliamentary secretary to a minister. The Act also provides that, for constitutional purposes, parliamentary secretaries are to be appointed as ministers of state, which enables them to be paid a salary.[1] In practice, parliamentary secretaries are the third level of ministerial positions, after cabinet ministers (who are members of the Cabinet of Australia) and other ministers.

According to Paul Keating in 1993, "the institution of Parliamentary Secretary provides a very inexpensive means not only of giving talented individuals executive experience but providing Ministers with needed support."[2] On 20 September 2015, Prime Minister Malcolm Turnbull announced that the title 'Parliamentary Secretary' is to be re-designated as 'Assistant Minister'.